The objectives of this research project is to determine the influence of protein, calorie, and vitamin deficiencies on oral mucous membranes in experimental animal model systems. Comparisons will be made between undernourished animals and those maintained on normal diets to determine the separate effects of chronic, progressive protein, calorie and vitamin deficiency on the health of the oral tissues. Tests conducted on the oral tissues of 3-4 year old Rhesus monkeys will determine; cell turnover rates; level of keratinization in deratinizing epithelium; degree of alteration of metabolic process (enzyme systems or protein synthsis); and studies of basement membranes of the various epithelial linings.